Sutured Floer homology distinguishes between Seifert surfaces

We exhibit the first example of a knot K in the three-sphere with a pair of minimal genus Seifert surfaces R 1 and R 2 that can be distinguished using the sutured Floer homology of their complementary manifolds together with the Spin c grading. This answers a question of Juhلsz. More precisely, we show that the Euler characteristic of the sutured Floer homology distinguishes between R 1 and R 2 , as does the sutured Floer polytope introduced by Juhلsz. Actually, we exhibit an infinite family of knots with pairs of Seifert surfaces that can be distinguished by the Euler characteristic.